/Engine/Source/Runtime/UMG/Public/Blueprint/WidgetBlueprintLibrary.h
Creates a new drag and drop operation that can be returned from a drag begin to inform the UI what i being dragged and dropped and what it looks like.
static [UDragDropOperation](API\Runtime\UMG\Blueprint\UDragDropOperation) * CreateDragDropOperation ( [TSubclassOf](API\Runtime\CoreUObject\Templates\TSubclassOf)< [UDragDropOperation](API\Runtime\UMG\Blueprint\UDragDropOperation) > OperationClass )